Hydrolysis and Oxidation Products of the Chemical Warfare Agents 1,2-Bis[(2-chloroethyl)thio]ethane Q and 2,2′-Bis(2-chloroethylthio)diethyl Ether T

Syntheses of diols of structure [HOCH₂CH₂S]₂(CH₂)_n in 86–95% yield from the sodium salt of 2-mercaptoethanol and Br(CH₂)_nBr (n = 1 to 5) or in 60–90% yield from 2-chloroethanol and NaS(CH₂)_nSNa (n = 2 to 5) are described. The diol [HOCH₂CH₂SCH₂CH₂]₂O was prepared in 82% yield from the sodium salt of 2-mercaptoethanol and [ClCH₂CH₂]₂O, and in 88% yield from 2-chloroethanol and [HSCH₂CH₂]₂O. Mono- and bis-sulfoxides and bis-sulfones of these species were prepared in generally high yield by treatment with an equivalent of KIO₄ in aqueous methanol, two equivalents of NaIO₄ in aqueous methanol, or four equivalents of H₂O₂ in trifluoroacetic acid respectively. The compounds are important analytical standards for investigating the fate of the chemical warfare agents sesquimustard Q and oxygen mustard T in environmental samples.     

Preparation and spectroscopic characterization of bis(6,8-dimethoxychroman-5-yl)methanes

3,5-Dimethoxyphenylalkan-2-ols react with diethoxymethane and boron trifluoride etherate, or aqueous formaldehyde and hydrochloric acid forming bis(6,8-dimethoxychroman-5-yl)methanes.     

Some regioselective reactions of photoaldrin and photodieldrin

A study has been made of the regioselectivities of some typical addition reactions of pbotoaldrin and epoxide ring-opening reactions of photodieldrin. The structures of the resulting products have been established by appropriate interconversions and syntheses. The factors responsible for the observed regioselectivities are discussed.     

Dark matter particle production in b-->s transitions with missing energy

Dedicated underground experiments searching for dark matter have little sensitivity to GeV and sub-GeV masses of dark matter particles. We show that the decay of B mesons to K(K(*)) and missing energy in the final state can be an efficient probe of dark matter models in this mass range. We analyze the minimal scalar dark matter model to show that the width of the decay mode with two dark matter scalars B-->KSS may exceed the decay width in the standard model channel, B-->Knunu , by up to 2 orders of magnitude. Existing data from B physics experiments almost entirely exclude dark matter scalars with masses less than 1 GeV. Expected data from B factories probe the range of dark matter masses up to 2 GeV.     

Einselection in action: decoherence and pointer states in open quantum dots

Recent work on the role of decoherence has suggested that the decay of quantum effects is governed by a discrete set of pointer states, which affect the quantum to classical correspondence. We show that the conductance oscillations exhibited by open quantum dots are governed by a discrete set of stable quantum states which have the properties of the pointer states, and which are closely related to trapped classical orbits in the open dot.     

Continuous analysis of δ18O and δD values of water by diffusion sampling cavity ring‐down spectrometry: a novel sampling device for unattended field monitoring of precipitation,ground and surface waters

A novel sampling device suitable for continuous, unattended field monitoring of rapid isotopic changes in environmental waters is described. The device utilises diffusion through porous PTFE tubing to deliver water vapour continuously from a liquid water source for analysis of δ¹⁸O and δD values by Cavity Ring‐Down Spectrometry (CRDS). Separation of the analysed water vapour from non‐volatile dissolved and particulate contaminants in the liquid sample minimises spectral interferences associated with CRDS analyses of many aqueous samples. Comparison of isotopic data for a range of water samples analysed by Diffusion Sampling‐CRDS (DS‐CRDS) and Isotope Ratio Mass Spectrometry (IRMS) shows significant linear correlations between the two methods allowing for accurate standardisation of DS‐CRDS data. The internal precision for an integration period of 3 min (standard deviation (SD) = 0.1 ‰ and 0.3 ‰ for δ¹⁸O and δD values, respectively) is similar to analysis of water by CRDS using an autosampler to inject and evaporate discrete water samples. The isotopic effects of variable air temperature, water vapour concentration, water pumping rate and dissolved organic content were found to be either negligible or correctable by analysis of water standards. The DS‐CRDS system was used to analyse the O and H isotope composition in short‐lived rain events. Other applications where finely time resolved water isotope data may be of benefit include recharge/discharge in groundwater/river systems and infiltration‐related changes in cave drip water. Copyright © 2011 John Wiley & Sons, Ltd.     

Creep in macromolecular solutions according to rigid dumbbell kinetic theory

The creep experiment is analyzed using the rigid-dumbbell suspension model. It is found that the equilibrium shear compliance J _e is given by $$J_e = \frac{{\theta _0 }}{{2\eta _0^2 }} + O(\kappa _\infty ^2 )$$ where η₀ and θ₀ are the viscosity and primary normal stress functions at zero-shear rate, and κ _∞ is the velocity gradient for large time. It is found that, to the lowest level of approximation, τ _yy ?τ _zz and τ _xx ?τ _yy have the same sign during the creep experiment.